Performance Evaluation of a DC Direct-Coupled PV System in comparison with a Typical Grid-connected AC System for a Commercial Building

Abstract:

With exponential hike in greenhouse gas emissions and depletion of fossil fuels, advancing renewable energy technology is the best available answer to global demands of clean and green energy. Solar Photovoltaic technology, although implemented worldwide, has a large further scope of improvement to create a fully accepted solar-powered society. One such concept can be a DC based photovoltaic system, which enables the use of DC power directly from solar panels without incorporating inverters. This thesis is based on a system-level PV project, which evaluates a newly installed DC direct-coupled system which uses DC power for office LED lighting, in comparison with existing conventional DC-AC photovoltaic systems. The main objective is to verify the efficiency of both the PV system setups for defining an optimal solution for energy performance and value proposition in order to propose this configuration for a larger market application and electric utility acceptance, in general. The system is studied by analyzing real-time data for a period of six months, measured for the various components that constitute the system and further compared on performance and economical grounds. At the end, it concludes with AC overall being a better and cheaper solution at present. Although, with slight modifications in the current scenario, DC can prove to be a better option in certain specific applications.